ABS Pump Motor Circuit Short to Ground
What does C0120 mean?
The C0120 code means the vehicle's onboard diagnostic system has detected: ABS Pump Motor Circuit Short to Ground. This is a critical severity code.
Common Symptoms
- ABS warning light on
- ABS fuse blows repeatedly
- Burning smell from ABS module area
- Complete loss of ABS function
- Traction and stability control lights on
Probable Causes (Ranked by Likelihood)
- Short circuit in ABS pump motor winding Very High
- Chafed wiring contacting ground High
- Water intrusion into ABS module connector Moderate
- Damaged ABS pump motor relay causing short Moderate
- ABS control module internal short Low
Step-by-Step Diagnostic Procedure
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Check the ABS pump motor fuse -- if blown, there is likely a short circuit
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Disconnect the pump motor connector and measure resistance to ground -- should be infinite
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Inspect all wiring in the pump motor circuit for chafing against the frame or body
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Look for water damage or corrosion at the ABS module connector
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Test pump motor in isolation to determine if the short is in the motor or wiring
Frequently Asked Questions
Why does my ABS fuse keep blowing?
A repeatedly blown ABS fuse is a strong indicator of a short to ground in the pump motor circuit. The short draws excessive current and blows the fuse as a safety measure. Do not keep replacing the fuse without finding the short.
Can water damage cause a C0120 code?
Yes. Water intrusion into the ABS module connector or pump motor is a common cause. Driving through deep water or pressure washing the engine bay can introduce moisture that creates a short circuit.
Is a short to ground dangerous?
A short to ground can cause overheating in the wiring and potentially start a fire if the fuse does not blow. Do not bypass the fuse. Repair the short circuit before restoring ABS function.